A. GREENBAUM ET AL., SCIENCE TRANSLATIONAL MEDICINE, 2017Originally derived to make see-through brains and other organs, the CLARITY tissue-clearing method also makes bone transparent, researchers reported today (April 26) in Science Translational Medicine. Although the opacity of bone is stripped away, genetically engineered fluorescent tags remain, allowing users to image glowing osteoprogenitor cells within the transparent bone marrow.
“Bone clarity allows for a whole range of questions that were not possible to previously address,” Corey Neu, a mechanical engineer at the University of Colorado Boulder who was not involved in the study, told Popular Science. Neu said the evidence presented today demonstrates a level of transparency he has not achieved in his own attempts to create see-through bone.
The technique first removes calcium from the bone, then stabilizes cellular structures with a hydrogel, before washing away lipids. Before the tissue-clearing, the mice had been genetically programmed to produce a red fluorescent label in bone stem cells.
The four-week process to clear the tissue is “not a fast method, by any means,” coauthor Viviana Gradinaru of Caltech told STAT News. “However, the result—there’s no substitute for getting 3-D access to the intact bone marrow.”
In collaboration with Amgen, the team used bone CLARITY to examine the effects of an osteoporosis drug.